1. Field of the Invention
The field of the invention is paneling for diffusive and absorptive sound control.
2. Description of the Related Art
Sound is generated from a source producing audible waves transmitted outward from the source. A listener in a room with the source receives sound waves directly from the source or indirectly from sound waves being reflected from objects in the room or from the boundaries defining the room. The quality of sound may be altered, and may even be enhanced, by placing physical objects in the path of propagating sound waves. By absorbing, reflecting or diffusing sound waves, the quality of the sound can be enhanced. Absorption of sound waves occurs when a sound wave strikes a barrier that is capable of absorbing the energy of the sound wave. For example, absorption of energy of a sound wave is accomplished by placing in the path of the sound wave energy absorbing materials. For instance, insulation materials of various thicknesses, carpet, acoustic ceiling tile, draperies and other heavy fabrics will absorb energy from sound waves that strike these objects. By this absorption the sound wave will gradually lose energy. If a room is capable of totally absorbing sound then the room is described by the art as being dead. Ideally, a certain degree of energy or sound absorption is acceptable in a listening room to prevent formation of standing waves and/or undesirable reinforcement or cancellation of sound. However, the listening room should not be so sound-absorptive that the room becomes dead, or that certain frequencies are lost due to absorption.
Reflection of sound waves occurs by changing the direction of a propagating energy wave without absorption. A hard surface, such as a drywall surface, wood, plaster or cement walls can function as devices for accomplishing reflection. The more dense the flat surfaces are the greater the ability of the surface to reflect sound. A certain amount of sound reflection is also considered desirable for listeners.
Diffusion, which is somewhat more complex than reflection or refraction, is a combination of reflection and refraction of the sound wave at the same time. That is, different segments or different frequencies emanating from a sound source when diffused will be delayed in time due to scattering or reflection of the wave. A sound source generally emits more than a single sound frequency. In diffusion, the different frequencies are reflected and scattered so that different frequencies are delayed in time. By provision of diffusion in a small recording studio, sounds in the studio can be perceived by the listener as being like those associated with a larger room, because the listener is exposed to the reflected, scattered and time delayed sound waves. Diffuser panels, used in the art, generally provide a means for achieving at least one dimensional sound diffusion, i.e., reflection and refraction in one direction.
U.S. Pat. No. 5,160,816 describes a two dimensional sound diffuser having projecting elements having heights of between 1½ inches and 9 inches. Hence, the panels are not flat and their maximum depth renders them less attractive for home theatres and the like.